Introducer with partially annealed reinforcement element and related systems and methods

ABSTRACT

The present disclosure illustrates an introducer sheath with a partially annealed metal frame. The introducer sheaths described herein include a hub coupled to a shaft. The shaft comprises a braided wire frame with (i) an annealed distal portion that prevents the braided wire frame from unraveling at a distal end, and (ii) a second portion that is unannealed; a jacket encompassing the braided wire frame; and a liner forming an inner wall.

RELATED APPLICATIONS

This application claims priority to U.S. Provisional Application No.62/491,770 titled “INTRODUCER WITH PARTIALLY ANNEALED REINFORCEMENTELEMENT AND RELATED SYSTEMS AND METHODS,” filed on Apr. 28, 2017, whichis hereby incorporated by reference in its entirety.

TECHNICAL FIELD

The present disclosure relates generally to medical sheaths includingintroducer sheaths and methods to manufacture introducer sheaths. Moreparticularly, some embodiments relate to introducer sheaths with apartially annealed reinforcement element.

BRIEF DESCRIPTION OF THE DRAWINGS

The written disclosure herein describes illustrative embodiments thatare non-limiting and non-exhaustive. Reference is made to certain ofsuch illustrative embodiments that are depicted in the figures, inwhich:

FIG. 1 is a perspective view of an introducer sheath with a sheath shaftincluding a partially annealed reinforcement element, according to oneembodiment.

FIG. 1A is a cross-sectional view, taken through line 1A-1A of a portionof the introducer sheath of FIG. 1.

FIG. 2A is a side view of an unannealed braided metal frame.

FIG. 2B is a side view of a partially annealed braided metal frame withan annealed distal portion.

FIG. 3 is a side view of a braided metal frame over a braiding core,according to one embodiment.

FIG. 4 is a side view of the braided metal frame of FIG. 3 disposed overan annealing mandrel.

FIG. 5A is a side view of the braided metal frame of FIGS. 3 and 4disposed over a liner loaded on a low surface friction mandrel.

FIG. 5B is a side view of the braided metal frame and liner of FIG. 5Aloaded on a low surface friction mandrel.

FIG. 6A is a side view of the braided metal frame, liner, and lowsurface friction mandrel of FIG. 5B with a jacket and fluorinatedethylene propylene (FEP) shell.

FIG. 6B is a side view the braided metal frame, liner, jacket, and FEPshell of FIG. 6A in a reflowed state to create a sheath assembly.

FIG. 7 is a side view of the assembly of FIG. 6B loaded on a cuttingmandrel.

FIG. 8 is a side view of the assembly of FIGS. 6B and 7 with a tipcoupled to the distal tip, according to one embodiment.

FIG. 9 is a side view of the sheath shaft with an overmolded tip.

FIG. 10 is a flow diagram of a method of manufacturing an introducersheath, according to one embodiment.

FIG. 11 is an exploded view of an introducer sheath with a shaftincluding a partially annealed reinforcement element, according to oneembodiment.

DETAILED DESCRIPTION

This disclosure describes medical sheaths with a partially annealedreinforcement element, such as a partially annealed braided frame, andmethods to manufacture such an introducer sheath. While embodimentsherein refer to introducer sheaths, the same features may be included onother types of sheaths such as guiding sheaths.

Introducer sheaths are used in a variety of diagnostic and therapeuticprocedures to provide access to a patient's vascular system. When anintroducer sheath is placed in the vasculature, the introducer sheathmay facilitate exchange of guidewires, catheters, contrast media, andvarious fluids while providing access to the vasculature and ahemostatic seal.

To facilitate the exchange of medical tools and fluids, the introducersheath includes a hub configured to remain exterior to the patient'sskin. The hub forms a chamber that may be accessed through variousports. For example, a hub may include a side port and an introducerbore. In some embodiments, the side port is fluidly coupled to a fluidchannel that is controlled by a stop-cock. The fluid channel conveysfluids or medicaments to and from the hub. A practitioner may introduceguidewires, catheters, stents, balloons, and other articles and/ormaterials to be introduced into the patient through the introducer bore.A valve or a seal may maintain hemostasis of the introducer sheath whileallowing a medical instrument to be introduced through the introducerbore into the chamber. The hub chamber is in fluid communication with asheath shaft. The sheath shaft is inserted into the vasculature of thepatient, and provides through the skin to the vasculature.

A problem with current sheaths is vascular access bleeding thatsometimes occurs after the sheath shaft has been removed. In general,there is a relationship between the size of the outer diameter of theinserted sheath shaft and the risk of bleeding complications. Thus,sheaths shafts with thinner walls correlate to a decrease in the size ofthe outside diameter (and therefore a decrease in the size of the holeat the vascular entry site) without decreasing the size of the insidediameter of the sheath. Thus, thin walled sheaths may reduce bleedingcomplications when compared to thicker wall sheaths with the same insidediameter.

However, simply reducing the thickness of the walls of a sheath shaftintroduces additional concerns. Specifically, with thinner walls, theremay be a greater concern of kinking and deformation from a cylindricalshape. When a sheath shaft kinks, the passageway to the vascular systemof a patient may be blocked. If a sheath shaft does not maintain itsshape, medical instruments may not fit.

To maintain the shape of a thin walled sheath shaft, the wall of theshaft may be reinforced. A polymer shaft may be reinforced with a metalreinforcing element, such as a braided metal frame. The reinforcingelement may thus increase the strength, stiffness, burst strength, creepresistance, and other properties of the shaft.

Braided metal frames may also have a desirable spring temper that bothresists kinks and increases the capacity of the shaft to temporarilyelastically deform, then spring back without creating a permanent kink.This, in turn, reduces instances where a kinked or deformed introducershaft must be removed and replaced during a therapy.

While a braided metal frame may thus increase strength, stiffness, andkink recovery, spring temper metal in the braid may also tend to unravelor fray on the end of a cut piece of braid during assembly of the shaft.Though this tendency to unravel may be contained by use of a thickerpolymer element around the braid, a thick polymer element also increasesthe wall thickness of the shaft. Annealing the braided metal frame, inthe braided condition, may lessen the tendency of the metal tounraveling, allowing for use of a metal reinforcing braid with a thinnerouter polymer element. In some applications, the entire braided metalframe is annealed. However, such an approach alters the spring temper ofthe entire braided metal frame and reduces the kink resistance andrecovery characteristics of the braided metal frame. In other words, aspring temper reinforcing element imparts desirable properties to anintroducer shaft, while an annealed reinforcing element may be easier toconstrain within an outer polymer layer.

Certain embodiments of introducer sheaths described herein use apartially annealed braided metal frame to both reduce wall thickness andmaintain a desirable wall stiffness, kink resistance, and kink recovery.Through only annealing a portion of the braided frame, the metal has areduced tendency to unravel along the annealed portion and the braidedframe maintains a desirable spring temper along the unannealed portions.

In some embodiments, an introducer shaft is coupled to a hub at aproximal end. The shaft forms a lumen that is in fluid communicationwith the chamber of the hub. The shaft may include a braided metal framewith an annealed distal portion and a second portion of the braidedmetal frame that is unannealed. The annealed distal portion reduced thetendency of the braided metal frame to unravel at a distal end. In someembodiments, the hub may prevent the braided metal frame from unravelingat the proximal end. In some embodiments, the braided metal frame mayinclude an annealed proximal portion. An outer polymer member such as ajacket may encompass the braided wire reinforcing element, and an innerpolymer member such as a liner may form an inside surface of the wall ofthe shaft.

Partially annealed introducer sheaths may be manufactured using themethods described in more detail below. In some embodiments, metal wiresare braided to form a frame of a sheath shaft. A distal portion of theframe is annealed to prevent the frame from unraveling at a distal end.A liner and a jacket are reflowing or melt-bonded onto the frame, and ahub is overmolded around a proximal portion of the reflowed shaft. Thesemethods may be done along a length sufficient to produce a plurality ofintroducer sheaths. For example, in some embodiments, a larger amount ofwire may be braided along a nylon core to form a frame. The nylon coremay be heated and stretched to reduce the diameter of the nylon core forremoval of the frame. A plurality of portions along the frame may beannealed. The portions that are annealed may correspond to ends of eachof a plurality of introducer sheaths to be formed from the initialbraid. A liner and a jacket may be reflowed to the inner and outersurfaces of the frame. The frame may be cut at the annealed portions toform a plurality of sheath shafts such that the annealed portions arelocated at a distal end of each of the plurality of sheath shafts. A hubmay be overmolded around a proximal portion of the sheath shafts.

The phrase “coupled to” is broad enough to refer to any suitablecoupling or other form of interaction between two or more entities,including mechanical, fluidic and thermal interaction. Thus, twocomponents may be coupled to each other even though they are not indirect contact with each other. The phrase “fluid communication” is usedin its ordinary sense, and is broad enough to refer to arrangements inwhich a fluid (e.g., a gas or a liquid) can flow from one element toanother element when the elements are in fluid communication with eachother.

The terms “proximal” and “distal” are opposite directional terms. Asused herein, the distal end of a device or component is the end of thecomponent that is furthest from the physician during ordinary use. Theproximal end refers to the opposite end, or the end nearest thephysician during ordinary use. For example, the proximal end of anintroducer sheath used in minimally invasive vascular treatment is theend accessible to a practitioner during use, while the distal end isdisposed within a patient's vascular system when the sheath is placedinto such a patient.

An assembler may be any person, system, or machine used in themanufacture of the introducer sheaths.

Embodiments may be understood by reference to the drawings, wherein likeparts are designated by like numerals throughout. The components of theembodiments as generally described and illustrated in the figures hereincan be arranged and designed in a wide variety of differentconfigurations. Thus, the following more detailed description of variousembodiments, as represented in the figures, is not intended to limit thescope of the present disclosure, but is merely representative of variousembodiments. While various aspects of the embodiments are presented indrawings, the drawings are not necessarily drawn to scale unlessspecifically indicated.

FIG. 1 is a perspective view of an introducer sheath 100 comprising asheath shaft 102 with a partially annealed reinforcement member,according to one embodiment. As shown, the introducer sheath 100 caninclude the sheath shaft 102 and a hub 110. The sheath shaft 102 iscoupled to and in fluid communication with the hub 110. During someprocedures, the hub 110 is intended to remain exterior of a patient, andthe sheath shaft 102 is intended to at least partially be placed withinthe vascular system of the patient.

The hub 110 forms a chamber that may be accessed via a side port 112 oran introducer bore 114. A suture ring 118 is coupled to the hub 110 andprovides a mechanism allowing a practitioner to grasp the introducersheath 100 while allowing the introducer sheath 100 to be sutured orfastened to the patient once the introducer sheath 100 has been properlyplaced. The side port 112 and the introducer bore 114 provide entry formedical devices and fluids. For example, a physician may insert adilator into the introducer bore 114 to assist with placing theintroducer sheath 100. The dilator enters the introducer bore 114through a seal or a valve that maintains hemostasis when the introducersheath 100 in in communication with the vasculature. Similarly, a fluidchannel 120 may couple to the side port 112, establishing a fluidpassageway with the chamber of the hub 110. In some embodiments, asleeve may be used to swage the fluid channel 120 onto the side port112. A sleeve 122 may be placed over the fluid channel 120 onto the sideport 112. Any medical instrument or fluids that enter the chamber of thehub 110 may continue through an opening at the hub distal end 116 into asheath shaft lumen 138. Thus, the side introducer bore 114 and a lumenof the fluid channel 120 may both be in fluid communication with thesheath shaft lumen 138.

FIG. 1A is a cross-sectional view, taken through line 1A-1A of a portionof the introducer sheath 100, showing elements of the sheath shaft 102.With reference to FIGS. 1 and 1A, the sheath shaft 102 includes anannealed portion 106 and an unannealed portion 108. A tip 104 is coupledto the sheath shaft 102. A cuff 124 may overlap the tip-shaft joint tostrengthen the joint. The sheath shaft 102 may be formed from a braidedmetal frame 134 with an exterior and interior surface coated with apolymer material. In the illustrated embodiment, a liner 132 is coupledto the interior surface of the braided metal frame 134 and defines theinside surface of the sheath shaft 102 and a jacket 136 is coupled tothe exterior surface of the braided metal frame 134 and defines theoutside surface of the sheath shaft 102. FIG. 1A may be understood asschematic in nature, though the liner 132, braided metal frame 134, andjacket 136 are shown as distinct layers, as further detailed below, thepolymer materials of the liner 132 and jacket 136 may be melted andreflowed together, bonding to the braided metal frame 134 and each otherand filling any openings in the braided metal frame 134.

The introducer sheath 100 may have a thinner wall when compared withtraditional introducer sheaths. In some embodiments, the introducersheath 100 may have an

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ratio of greater than 0.85. For example, an introducer sheath for a 4French (4 F) needle or catheter may have an

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ratio of greater than 0.85, an introducer sheath for a 5 F needle orcatheter may have an

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ratio of greater than 0.87, an introducer sheath for a 6 F needle orcatheter may have an

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ratio of greater than 0.89, an introducer sheath for a 7 F needle orcatheter may have an

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ratio of greater than 0.90. In some embodiments, the introducer sheath100 may have an

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ratio ranging between 0.87 and 0.93. For example, an introducer sheathfor a 4F needle or catheter may have an average

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ratio ranging between 0.87 and 0.89, an introducer sheath for a 5 Fneedle or catheter may have an average

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ratio ranging between 0.89 and 0.90, an introducer sheath for a 6 Fneedle or catheter may have an average

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ratio ranging between 0.90 and 0.91, and an introducer sheath for a 7 Fneedle or catheter may have an average

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ratio ranging between 0.92 and 0.93.

The annealed portion 106 and the unannealed portion 108 of the sheathshaft 102 may correspond to portions along the length of the sheathshaft 102 where the braided metal frame 134 is annealed or unannealed,respectively. The term unannealed refers to portions of the braidedmetal frame 134 that retain or otherwise are configured with more springtemper than the annealed portion 106. The tip 104 may be coupled to thesheath shaft 302 adjacent the annealed portion 106. In some embodiments,the tip 104 lacks a metal frame, making the tip 104 more malleable toreduce trauma and increase trackability over a guidewire when theintroducer sheath 100 enters the vascular system. In some embodiments, acuff may be positioned across the joint between the tip 104 and theannealed portion 106. The cuff may smooth the transition between the tip104 and the annealed portion 106 and increase the strength of the joint.

FIG. 2A is a side view of an unannealed braided metal frame 234 a andFIG. 2B is a side view of a partially annealed braided metal frame 234 bwith an annealed distal portion 206 b. (In FIGS. 2A and 2B, analogousportions are designated with analogous reference numerals followed by an“a” or “b” corresponding to each figure.) The braided metal frames 234 aand 234 b of FIGS. 2A and 2B resembles the braided metal frame 134 ofFIG. 1, described above, in certain respects. Accordingly, like featuresare designated with like reference numerals, with the leading digitsincremented to “2.” For example, the embodiment depicted in FIGS. 1 and1A includes an unannealed portion 108 that may, in some respects,resemble the unannealed portions 208 a and 208 b of FIGS. 2A and 2B.Relevant disclosure set forth above regarding similarly identifiedfeatures thus may not be repeated hereafter. Moreover, specific featuresof the braided metal frames 234 a and 234 b and related components shownin FIGS. 2A and 2B may not be shown or identified by a referencenumerals in the drawings or specifically discussed in the writtendescription that follows. However, such features may clearly be thesame, or substantially the same, as features depicted in otherembodiments and/or described with respect to such embodiments.Accordingly, the relevant descriptions of such features apply equally tothe features of the embodiments of FIGS. 2A and 2B. Any suitablecombination of the features, and variations of the same, described withrespect to the introducer sheath 100 and related components illustratedin FIGS. 1 and 1A can be employed with the embodiments and relatedcomponents of FIGS. 2A and 2B, and vice versa. This pattern ofdisclosure applies equally to further embodiments depicted in subsequentfigures and described hereafter, wherein the leading digits may befurther incremented.

FIG. 2A illustrates how an unannealed metal frame 234 a, having a springtemper, tends to unravel. The spring temper of the fibers of theunannealed metal frame 234 a have a tendency to straighten themselvesfrom the braided configuration due to the spring temper, and thusunravel if unconstrained.

FIG. 2B is a side view of a partially annealed braided metal frame 234 bwith an annealed portion 206 b. The annealed portion 206 b is located atthe distal end of the braided metal frame 234 b. Annealing the annealedportion 206 b removes residual stresses and the spring temper of thebraided metal frame 234 b along the annealed portion 206 b. Whenannealed, the fibers of the annealed portion 206 b do not tend toself-straighten and unravel in the same manner as the unannealed fibersof the braided metal frame 234 a of FIG. 2A.

The presence of the annealed portion 206 b at the distal end of thebraided metal frame 234 b also helps maintain the braid along theunannealed portion 208 b of the braided metal frame 234 b. Though thefibers along the unannealed portion 208 b retain their spring temper,interaction with adjacent fibers and with the annealed portion 206 bmitigates the ability of these fibers to self-straighten such that theyunravel. Thus, the annealed portion 206 b may prevent the remainingunannealed portion 208 b from unraveling like the unannealed braidedmetal frame 234 a in FIG. 2A. Thus, the partially annealed braided metalframe 234 b may maintain the spring temper of an unannealed braidedmetal frame along the majority of its length and while still tending toremain in its tubular braided shape without outside constraints thatwould be required to retain the shape of a wholly unannealed braidedmetal frame.

In some embodiments the annealed portion 206 b may be from approximately1/32 inches long to approximately ¼ inches long, including from about1/16 inches long to about 3/16 inches long and about ⅛ inches long.

FIGS. 3-9 illustrate various stages of manufacture of an introducersheath with a partially annealed shaft, such as introducer 100illustrated in FIG. 1. As noted in the explanation of the relationshipof FIGS. 1 and 1A to FIGS. 2A and 2B, above, the elements andembodiments of FIGS. 3-9 may analogously relate to elements andembodiments of other figures. Again, like elements are referenced withlike reference numerals with the leading digits incremented. Disclosurerelated in connection with one embodiment may analogously be applied tothe other embodiments, and vice versa.

Further, FIGS. 3-9 depict certain exemplary manufacturing instrumentsthat may be used to create an introducer sheath, such as introducersheath 100. Additionally, the manufacturing instruments may be used invarious method steps, including those steps depicted in FIG. 10.

FIG. 3 is a side view of a braided metal frame 334 over a braiding core340, according to one embodiment. The braiding core 340 provides asurface for the wires to be braided around to form the braided metalframe 334.

The braided metal frame 334 may be made from wires with a desired springtemper. For example, tempered steel or brass wires may have a desiredspring temper induced to increase their upper limit of elasticity.Steels used in the braided metal frame 334 may include stainless steel,low-alloy, medium-carbon steel, nitinol, and high-carbon steel includingthose with high yield strength. In some embodiments, one or moreradiopaque strands of material may be used in the braided metal frame334. For example one or more wires of palladium, platinum, depleteduranium, or high radiopaque wire may be weaved into the braided metalframe 334 for fluoroscopy identification. In some embodiments, markerbands may be integrated into the braided metal frame 334 for fluoroscopyidentification. The spring temper of the wires may allow the braidedmetal frame 334 to return to its original shape despite deflection,deformation, and/or twisting. In some embodiments, the braided metalframe 334 may include flat wires. In other embodiments, the braidedmetal frame 334 may include round wires. In yet other embodiments, thebraided metal frame 334 may include a combination of flat and roundwires. Each strand of the braided metal frame 334 may include one ormore wires. For example, a five-strand bobbin may be used to braid aframe with five wires in every braid. The tightness of the weave of thebraided metal frame 334 may be altered to adjust the stiffness andflexibility of the introducer sheath.

The braiding core 340 may comprise a thermoplastic that becomes pliableor moldable above a specific temperature and solidifies upon cooling.For example, in some embodiments, nylon may be extruded to form thebraiding core 340. The diameter of the braiding core 340 corresponds tothe inside diameter of the braided metal frame 334, which thus relates(when adjusted for polymer lines and jackets) to the finished outsideand inside diameters of a finished sheath shaft (such as sheath shaft102 of FIG. 1) of an introducer sheath. When the braided metal frame 234has been created, an assembler may heat the braiding core 340 to a pointthat the thermoplastic becomes pliable, and stretch the braiding core340. Stretching the braiding core 340 causes the braiding core 340 toneck down, resulting in a longer core with a smaller diameter. Thesmaller diameter allows an assembler to easily remove the braiding core340 from the braided metal frame 334.

FIG. 4 is a side view of the braided metal frame 334 disposed over anannealing mandrel 342. After the braiding core 340 of FIG. 3 is removed,an assembler may load the braided metal frame 334 on the annealingmandrel 342 to anneal at least a portion of the braided metal frame 334.

In some embodiments, an assembler uses electromagnetic waves such asradio frequency (RF) or microwaves to selectively anneal portions of thebraided metal frame 334. For example, RF radiation may be applied to aportion of the braided metal frame 334 to anneal the material along thatportion to form an annealed portion 306. The braided metal frame 223 maybe selectively annealed by transferring heat to the braided metal frame223 using a heated element or a flame. The annealed portion 306 may bedisposed near the distal tip 335 of the braided metal frame 334. Theannealing process allows for crystalline restructuring between adjacentbraids of the annealed portion 306. The crystalline restructuring of theannealed portion 306, such as at the intersection between adjacentbraids, may tend to prevent the unannealed portion 108 from unraveling.Additionally, annealing may reduce the tendency of the braids tostraighten out, also tending to prevent unraveling.

The length of the annealed portion 306 may vary based on application. Insome embodiments, the annealed portion 306 may be from approximately1/32 inches long to approximately ¼ inches long, including from about1/16 inches long to about 3/16 inches long and about ⅛ inches long. Insome embodiments, a plurality of portions on the length of a longbraided metal frame may be annealed. The long braided metal frame maysubsequently be cut to form multiple braided metal frames for inclusionin introducer sheath shafts. The positions of the plurality of annealedportions along the long braided metal frame may thus ultimatelycorrespond to portions that will be disposed as distal ends of aplurality of introducer sheath shafts.

FIG. 5A is a side view of the braided metal frame 334 over a liner 332loaded on a low surface friction mandrel 344. Low surface frictionmandrel 344 may be formed from or coated with low friction materials toease loading and removal of the liner 332 and braided metal frame 334.For example, in some embodiments, the low surface friction mandrel 344may be a polytetrafluoroethylene (PTFE) to slide a stainless steel metalframe onto. In some embodiments, lubricants may be used to reduce thefriction on the surface of the low surface friction mandrel 344.

The liner material may comprise polyamide resins configured to seal theinterior surface of the braided metal frame 334. The liner 332 caninclude a surface comprising a lubricious polymeric material. Forexample, the material can comprise any bio-compatible material havinglow frictional properties (e.g., TEFLON®, PTFE, fluorinated ethylenepropylene (FEP), polyethylene, polyamide, ethylenechlorotrifluoro-ethylene, ethylene tetrafluoroethylene, PVDF).

As shown, when the braided metal frame 334 is slid over the liner 332,the fibers of the braided metal frame 334 may tend to bunch forming abunched section 334 a. Such bunching may result in the braided metalframe 334 becoming non-uniform. Non-uniformity, in turn, may causeinconsistencies along the surface of the introducer sheath shaft, andalter the flexibility along the introducer sheath shaft. Therefore, insome embodiments, the braided metal frame 334 may be stretched afterbeing placed on the liner 332 to restore uniformity as shown in FIG. 5B.In some embodiments, the braided metal frame 334 may be braided directlyonto the mandrel and annealing may occur while braiding. This mayprevent bunching of the braided metal frame 334.

FIG. 5B is a side view of the braided metal frame 334 with astraightened section 334 b (e.g., the bunched section of FIG. 5Astretched to restore uniformity) disposed over the liner 332 and loadedon the low surface friction mandrel 344. As shown, an assembler maystretch the braided metal frame 334 until it is approximately uniform. Aproximal portion 337 may be twisted down against the liner 332 and lowsurface friction mandrel 344 after stretching. The twisting may securethe proximal portion 337 in place and cause the remainder of the braidedmetal frame 334 to maintain its shape and position. The uniformity ofthe braided metal frame 334 results in a similar flexibility, kinkresistance, and diameter along the entire length of the introducersheath shaft. The step of stretching the braided metal frame 334 torestore uniformity may not be needed in instances wherein the braidedmetal frame 334 is slid over the liner 332 in such a manner as to retainits uniform consistency.

FIG. 6A is a side view of the braided metal frame 334 and the liner 332loaded on the low surface friction mandrel 344, with a jacket 336disposed over the braided metal frame 334 and an FEP shell 346 disposedover the jacket 336. The jacket 336 may have a hydrophilic coating and alarger diameter than the braided metal frame 334. The FEP shell 346 mayhave a larger diameter than the jacket 336 and encompass the jacket 336,braided metal frame 334, and liner 332.

All of the components may be heated to melt or reflow the liner 332 andthe jacket 336 as shown in FIG. 6B. Heating the FEP shell 346 causes itto shrink, reducing its diameter. The reduced diameter of the FEP shell346 causes the sidewalls of the FEP shell 346 to apply pressure to theencompassed elements (i.e., the jacket 336, braided metal frame 334, andliner 332). The reflow temperature is within a range that causes thejacket 336 and liner 332 to melt, but not the FEP shell 346. Thus, thejacket 336 and liner 332 are reflowed to the metal frame 334 to create acomposite conduit forming a sheath shaft 302.

FIG. 7 is a side view of the sheath shaft 302 loaded on a cuttingmandrel 347. As shown, the distal and proximal ends of the sheath shaft302 have been cut and removed. In some embodiments, part of the annealedportion 306 is removed, ensuring that the distal tip 335 of the braidedmetal frame 334 comprises an edge of the annealed portion 306.

FIG. 8 is a side view of the sheath shaft 302 with a tip 304 coupled tothe composite conduit sheath shaft 302 adjacent the distal tip 335 ofthe braided metal frame 334. The tip 304 may comprise a polymericmaterial configured to be malleable to reduce trauma when the introducersheath enters the vascular system and increase trackability of theintroducer over a guidewire. A butt joint may couple the tip 304 to thesheath shaft 302. A butt joint ensures smoothness through the transitionfrom the tip 304 to the sheath shaft 302. In some embodiments, the tip304 may overlap the sheath shaft 302. In some embodiments, a cuff 124may overlap the tip 304 and the annealed section of the sheath shaft 302to strengthen the butt joint. Coupling the tip 304 to the sheath shaft302 may be accomplished via a similar method as was described withreference to FIGS. 6A-6B. Specifically, the components may be loaded ona low surface friction mandrel 348 (not necessarily the same low surfacefriction mandrel 344 discussed above, though it may be). An FEP shell349 (not necessarily the same FEP shell 346 discussed above) mayencompass the tip 304 and the sheath shaft 302. Heat may cause the FEPshell 349 to shrink and apply pressure while the tip 304 melts to thesheath shaft 302.

FIG. 9 is a side view of the sheath shaft 402 with an overmolded tip404. As shown, the tip 404 may couple to the sheath shaft 402 at adistal end and may be coupled via an overmolding process. Similarly, thehub (not shown) may be overmolded at a proximal end of the sheath shaft402. In some embodiments the tip 404 may be more radiopaque than othercomponents to facilitate imaging.

FIG. 10 is a flow diagram of an example of a method 1000 ofmanufacturing an introducer sheath, according to one embodiment. Thesteps shown in FIG. 10 may be optional and not necessarily including ineach process. Further, various steps may be completed in differentsequences from those shown in FIG. 10.

In the illustrated process of FIG. 10, an assembler extrudes 1002 anylon core and braids 1003 a metal fame over the core. The assemblerthen heats and stretches 1004 the core and removes the braid. Theassembler loads 1005 the braid onto an annealing mandrel. RF anneals1006 a portion of the braid.

A liner is extruded 1007 and slides 1008 over a PTFE-coated mandrel. Theassembler slides 1009 the annealed braid over the liner. The back of thebraid is twisted 1010 down, and any excess braid is trimmed. Theassembler stretches 1011 the braid for uniformity. The assemblerextrudes 1012 a jacket, and extrudes 1014 an FEP heat shrink shell. Theassembler slides 1013 the extruded jacket over top of the braid, andslides 1015 the FEP shell over the jacket. The assembly is exposed toheat, causing the liner and the jacket to reflow 1016.

The FEP shell is removed 1017, and the assembly is removed 1018 from themandrel. The assembler extrudes 1020 a sacrificial cutting mandrel andslides 1019 the assembly over the cutting mandrel. The assembler uses acarbide blade to cut 1021 the ends of the assembly. The assemblerextrudes 1022 a tip and joins 1023 the assembly to the tip using a buttjoint. The assembler may place a cuff overlapping 1030 the butt jointfor additional strength. The assembler slides 1024 an FEP shell over thejoint and uses a split die fuser to bond 1025 the tip to the assembly.The assembler removes 1026 the assembly from the FEP shell and themandrel and overmolds a hub 1027 and a radiopaque tip 1028. Theassembler coats 1029 the assembly with a hydrophilic coating.

FIG. 11 is an exploded view of an introducer sheath 500 with a partiallyannealed sheath shaft 502, according to one embodiment. A hub 510 mayprovide access to the sheath shaft 502 for medical instruments such as adilator 50. Further, the sheath shaft 502 may comprise a liner 532,braided metal frame 534, jacket 536, and cuff 524. The sheath shaft 502elements may be coupled via a reflow process that melt-bonds theelements together. A tip 504 is coupled to the sheath shaft 502.

Any methods disclosed herein comprise one or more steps or actions forperforming the described method. The method steps and/or actions may beinterchanged with one another. In other words, unless a specific orderof steps or actions is required for proper operation of the embodiment,the order and/or use of specific steps and/or actions may be modified.

References to approximations are made throughout this specification,such as by use of the term “near.” For each such reference, it is to beunderstood that, in some embodiments, the value, feature, orcharacteristic may be specified without approximation. For example,where qualifiers such as “near” and “approximately” are used, theseterms include within their scope the qualified words in the absence oftheir qualifiers. For example, where the term “approximately aligned” isrecited with respect to a feature, it is understood that in furtherembodiments, the feature can have a precisely aligned configuration.

Reference throughout this specification to “an embodiment” or “theembodiment” means that a particular feature, structure, orcharacteristic described in connection with that embodiment is includedin at least one embodiment. Thus, the quoted phrases, or variationsthereof, as recited throughout this specification are not necessarilyall referring to the same embodiment.

Similarly, in the above description of embodiments, various features aresometimes grouped together in a single embodiment, figure, ordescription thereof for the purpose of streamlining the disclosure. Thismethod of disclosure, however, is not to be interpreted as reflecting anintention that any claim require more features than those expresslyrecited in that claim. Rather, as the following claims reflect,inventive aspects lie in a combination of fewer than all features of anysingle foregoing disclosed embodiment.

The claims following this written disclosure are hereby expresslyincorporated into the present written disclosure, with each claimstanding on its own as a separate embodiment. This disclosure includesall permutations of the independent claims with their dependent claims.Moreover, additional embodiments capable of derivation from theindependent and dependent claims that follow are also expresslyincorporated into the present written description.

Without further elaboration, it is believed that one skilled in the artcan use the preceding description to utilize the invention to itsfullest extent. The claims and embodiments disclosed herein are to beconstrued as merely illustrative and exemplary, and not a limitation ofthe scope of the present disclosure in any way. It will be apparent tothose having ordinary skill in the art, with the aid of the presentdisclosure, that changes may be made to the details of theabove-described embodiments without departing from the underlyingprinciples of the disclosure herein. In other words, variousmodifications and improvements of the embodiments specifically disclosedin the description above are within the scope of the appended claims.Moreover, the order of the steps or actions of the methods disclosedherein may be changed by those skilled in the art without departing fromthe scope of the present disclosure. In other words, unless a specificorder of steps or actions is required for proper operation of theembodiment, the order or use of specific steps or actions may bemodified. The scope of the invention is therefore defined by thefollowing claims and their equivalents.

1. An sheath comprising: a hub forming a chamber and comprising: a sideport in fluid communication with the chamber, and an introducer borewith a seal to maintain hemostasis of the introducer sheath whileallowing a medical instrument to be introduced through the introducerbore into the chamber; and a shaft coupled to the hub at a proximal end,the shaft forming a lumen that is in fluid communication with thechamber of the hub, the shaft comprising: a braided wire frame with anannealed distal portion preventing the braided wire frame fromunraveling at a distal end during assembly, a second portion of thebraided wire frame being unannealed, the second portion maintainingphysical properties of spring temper wire. a jacket encompassing thebraided wire frame, and a liner forming an inner wall, the linerencompassed by the braided wire frame.
 2. The sheath of claim 1, whereinthe hub is overmolded around a proximal portion of the shaft.
 3. Thesheath of claim 1, wherein the hub prevents a proximal end of thebraided wire frame from unraveling.
 4. The sheath of claim 1, wherein aproximal portion of the braided wire is annealed.
 5. The sheath of claim1, wherein the jacket and the liner are reflowed to the braided wireframe.
 6. The sheath of claim 1, wherein the jacket comprises ahydrophilic coating.
 7. The sheath of claim 1, wherein the braided wireframe comprises stainless steel.
 8. The sheath of claim 1, wherein thebraided wire frame comprises flat wires and round wires.
 9. The sheathof claim 1, wherein the shaft comprises an inner diameter outer diameterratio greater than 0.85.
 10. The sheath of claim 1, wherein the shaftcomprises an inner diameter outer diameter ratio ranging between 0.87and 0.93.
 11. The sheath of claim 1, further comprising a radiopaque tipcoupled to a distal end of the shaft.
 12. A method of manufacturing asheath, comprising: braiding metal wires to form a frame of a sheathshaft; annealing a distal portion of the frame to prevent the frame fromunraveling at a distal end during assembly; reflowing a liner to aninterior surface of the frame; reflowing a jacket to an exterior surfaceof the frame; and overmolding a hub around a proximal portion of theframe to prevent the frame from unraveling at a proximal end, the hubhaving a chamber in fluid communication with a hollow conduit formedfrom reflowing the liner and jacket to the frame, a side port in fluidcommunication with the chamber, and an introducer bore with a seal tomaintain hemostasis of the introducer sheath while allowing a medicalinstrument to be introduced through the introducer bore into thechamber.
 13. The method of claim 12, further comprising: extruding anylon core, wherein braiding the metal wires is performed over the nyloncore causing the frame to have an interior diameter equivalent to adiameter of the nylon core; heating and stretching the nylon core toreduce the diameter of the nylon core; and sliding the frame off of thenylon core.
 14. The method of claim 12, wherein annealing the distalportion of the frame comprises: loading the frame onto an annealingmandrel; and applying radio frequency energy to the distal portion ofthe frame.
 15. The method of claim 12, wherein reflowing the liner andthe jacket comprises: loading the liner onto a mandrel; sliding theframe over the liner; sliding the jacket over the top of the frame; andapplying heat and pressure to the jacket.
 16. The method of claim 15,wherein the mandrel is coated with polytetrafluoroethylene.
 17. Themethod of claim 15, further comprising twisting the proximal end of theframe and trimming excess metal wires.
 18. The method of claim 15,further comprising stretching the frame for uniformity.
 19. The methodof claim 15, wherein applying heat and pressure to the jacket is doneusing fluorinated ethylene propylene tubing.
 20. The method of claim 12,further comprising adjoining a tip to the distal end of the sheathshaft.
 21. The method of claim 12, further comprising overmolding aradiopaque tip on the distal end of the sheath shaft.
 22. The method ofclaim 12, wherein only a distal portion of the frame is annealed.
 23. Amethod of manufacturing a sheath, comprising: extruding a nylon core;braiding metal wires over the nylon core to form a frame; heating andstretching the nylon core to reduce the diameter of the nylon core forremoval of the frame; annealing a plurality of portions of the frame;reflowing a liner to an interior surface of the frame and a jacket to anexterior surface of the frame to form a composite conduit; cutting thecomposite conduit at the annealed portions to form a plurality of sheathshafts such that the annealed portions are located at a distal end ofeach of the plurality of sheath shafts, the annealed portions being lessthan a length of each of the sheath shafts; and overmolding a hub arounda proximal portion of the sheath shafts.